Jettison system for discharging fluid from a ship at sea



17967- .A. D. PAOLI 3,351,036

JETTISON SYSTEM FOR DISCHARGING FLUID FROM A SHIP AT SEA Filed March 18,1966 2 Sheets-Sheet 1 ATTORNEY Nov. 7, 1967 A. D. PAOLI 3,

JETTISON SYSTEM FOR DISCHARGING FLUID FROM A SHIP AT SEA Filed March 18,1966 2 Sheets-Sheet 2 INVENTOIR fiLEXA/vQE/KDHA 2404 ATTORNEY 3,351,036JETTISON SYSTEM FOR DISCHARGING FLUID FROM A SHIP AT SEA Alexander DelliPaoli, Huntington Station, N.Y., assignor to Esso Research andEngineering Company, a corporation of Delaware Filed Mar. 18, 1966, Ser.No. 535,513 4 Claims. (Cl. 114-183) ABSTRACT OF THE DISCLOSURE Aretractable framework at the stern of a ship is movable to place the endof a liquid cargo jettison conduit below the level of the sea water. Afoil section carried by the framework provides downward thrust on thejettison conduit framework to maintain its discharge below the seawater. Pulley and lifting strut mechanism are employed for raising andlowering the framework.

The present invention relates to jettison systems.

In particular, the present invention relates to jettison systems adaptedto be used for discharging fluids from a ship at sea.

The structure of the invention is intended primarily to be used by atanker carrying a fluid which may create dangerous conditions if thefluid escapes from a cargo tank while the tanker is at sea. Such a fluidmay be, for example, liquefied natural gas, hereinafter referred to asLNG. It is customary to transport LNG in the form of a liquid. In orderto maintain the LNG in liquid form at atmospheric pressure, thetemperature of the LNG must be lowered to 259 F. Of course, the cargotank itself has a storage capable of withstanding such low temperatures.However, the ships hull is made of ordinary carbon steel which wouldembrittle and fracture at 259 F., so that if it should happen that anyof the LNG leaks from a cargo tank, it is necessary for safety purposesto pump the LNG overboard when such a leak is detected.

It is, therefore, a primary object of the invention to provide, as asafety device for a tanker, a jettison system capable of discharging afiuid such as LNG, or, in fact, any other dangerous fluid.

In particular, it is an object of the invention to provide a jettisonsystem of this type which can quickly and easily be displaced from astowed position to an operative position where discharge of the fluidwill quickly and efliciently be carried out.

Furthermore, it is an object of the invention to provide a jettisonsystem whose parts are quite simple while at the same time capable ofoperating very reliably to place the system either in its stowed or inits operative position.

Also, it is an object of the invention to provide a jettison systemwhich takes advantage of such factors as the thrust derived from thedischarging fluid and the motion of the ship with respect to the sea soas to tend to reliably maintain the parts in their operative positionwhile the ship remains under Way.

The jettison system of the invention includes a conduit means whichcommunicates with the fluid which may have to be discharged at sea. Thisconduit means has an exterior portion situated at the exterior of theship and terminating in a discharge nozzle. A mounting means of theinvention mounts the exterior portion of the conduit means for movementbetween an upper, inoperative stowed position and a lower, operativedischarge position Where the fluid is discharged through the conduitmeans and out through the discharge nozzle to the sea.

The invention is illustrated by way of example in the accompanyingdrawings which form part of the application and in which:

I United States Patent Ofifice 3,351,936 Patented Nov. 7, 1967 FIGURE 1fragmentarily and schematically illustrates the side view of the sternof a ship carrying the jettison system of the invention in the stowed,inoperative position in solid lines and in the operative position indotdash lines;

FIGURE 2 is an elevation view of the jettison system of the invention asit appears when looking forward toward the stern of the ship, the systembeing shown in its stowed position in FIGURE 2;

FIGURE 3 is a side elevation, partly in section, of the structure ofFIGURE 2 taken along line 3-3 of FIGURE 2 in the direction of thearrows, with part of the structure broken away in FIGURE 3 so as to moreclearly illustrate the details of the structure;

FIGURE 4 is a fragmentary sectional side view of a mounting bracket andthe parts carried thereby;

FIGURE 5 is a fragmentary partly sectional top plan view taken alongline 5--5 of FIGURE 3 in the direction of the arrows and showing theparts in their stowed position;

FIGURE 6 is a top plan view taken along line 6-6 of FIGURE 4 in thedirection of the arrows and showing the parts in their operativeposition; and

FIGURE 7 is a perspective illustration of one of the mounting bracketsof the jettison system of the invention.

Referring now to FIGURE 1, the transom 10 of a ship 12 is fragmentarilyand schematically illustrated. A conduit means 14 communicates with acargo tank which carries the fluid, such as LNG, which may have to bedischarged while the ship 12 is under way, in the event that a leak fromthe cargo tank is detected. The conduit means 14 has an exterior portionmade up of a stationary tubular part 16 and a movable tubular part 18.As is shown most clearly in FIGURE 2, the stationary tubular part 16, inthe form of a suitable pipe or hose, is fixed directly to the transom orstern 10 by suitable clips 20. A fluid tight swivel joint 22 ofconventional construction is also fixed to the stern 10, and thestationary tubular part 116 communicates with the swivel joint 20. Themovable tubular part 18 of the conduit means 14 also communicates withthe swivel joint 20, so that the movable tubular part 18 can turn withrespect to the stationary part 16 of the conduit means about the axisprovided by the swivel joint 22.

The end portion of the conduit means 14 terminates in a discharge nozzle24 which is curved at the end of the tubular part 18 so as to direct thedischarging fluid in a given direction for a purpose described below. Itwill be understood that the parts 16, 18, and 24 may be provided with asuitable exterior insulation to prevent excessive buildup of icethereabout during LNG discharge.

A mounting means mounts the conduit means 18 for movement between thestowed position shown in solid lines in FIGURE 1 and the operativeposition shown in dot-dash lines in FIGURE 1. In its lower operativeposition, the discharge nozzle 24 is situated at an elevation preferablyno higher than the waterline. In FIGURE 1 the discharge nozzle 24 isshown in dot-dash lines slightly below thewaterline, so that when thefluid is pumped out through the conduit means 14 it will discharge awayfrom the stem 10 providing at the discharge nozzle 24 a thrust of thedischarge nozzle 24 toward the stem 10. In this way the parts will tendto be maintained in their operative position due to their own weight andthe nozzle thrust, as will be apparent more clearly from the descriptionbelow.

The mounting means of the invention is formed by the structure shown inFIGURE 2 carrying the movable part 18 of the conduit means. Thisstructure includes a pivot support means formed by a pair of brackets24a and 24b, and a frame means 26 formed by an A-frarne 28 whichdirectly carries the movable conduit portion 18.

The support means supports the frame means 26 for movement between theupper stowed position, shown in solid lines in FIGURE 1, and the loweroperative position shown in dot-dash lines in FIGURE 1. A cable 30 isconnected to the A-frame 28 and forms a moving means for moving theframe means 26 with respect to the support means between the loweroperative position and the upper stowed position. This cable 30 isconnected to a suitable winch (not shown) which can be operated to paythe cable out so as to lower the frame means 26 to its operativeposition or to wind the cable up so as to return the frame means 26 toits stowed position.

The jettison system also includes, in the illustrated example, a liftingstrut 32 which is substantially coextensive with the A-frame 28, as isapparent from FIG- URE 2. This lifting strut 32 carries a pulley 34around which the cable 30 is guided so that efiicient raising of theframe means 26 will be provided. As will also be apparent, the operationof strut 32 also prevents any possibility of toggling of the A-frame 28when it is raised from the operative to the stowed position.

The pair of brackets 24a and 24b respectively have walls 36a and 36bwhich are directly fixed to the hull of the ship at its stern It). Thebracket 24a has a pair of outer webs 38a and an intermediate web 40asituated between and equidistantly spaced from the outer webs. All ofthese webs are integral with and extend from the wall 36a of the bracket24a. In the same way the bracket 36b has a pair of outer webs 38b and anintermediate web 40b situated substantially midway between the outerwebs 38b. These webs are all parallel to each other and are situated insubstantially vertical planes. The webs of the bracket 24a carry a pivot42a in the form of a suitable horizontal pivot pin extending throughsuitable coaxial bores of the webs 38a and 40a. In the same way the websof the bracket 24b carry a pivot 42b.

The A-frame 28 terminates in a pair of free ends 4411 and 44b throughwhich the pivots 42a and 42b respectively extend, and these ends 44a and44b of the A-frame are situated between the intermediate webs Mia and46b, on the one hand, and the outermost webs 38a and 381), on the otherhand. The turning axis defined by the coaxial pivots 42a and 42bcoincides with the turning axis provided by the fluid-tight swivel joint22, so that the movable tubular part 18 will turn about the same axis asthe A-frame 28. The A-frarne includes a rigid crossbar 46 fixedlycarrying a tubular clip 47 (FIG- URE 3) by which the tubular part 18 isdirectly fixed to and carried by the A-frame 28 for movement therewith.

At the extremities of its free ends 44a and 44b, the A-frame 28 fixedlycarries a pair of fingers 48 which extend behind the lifting strut 32for a purpose described below. These fingers may be formed integrallywith the A-frame. FIGURES 3, 5, and 6 show the finger 48 which is fixedto the end 44b of the A-frame. This finger 48 is of a substantiallyL-shaped configuration and extends through a notch 56 (FIGURE 3) of theintermediate web 4% into the space behind the lower right end of thestrut 32, as viewed in FIGURE 2. In the same way, the left end 44a ofthe A-frame 28, as viewed in FIGURE 2, carries a finger which is in allrespects symmetrical with the finger 48 and which extends behind theleft lower end of the strut 32, as viewed in FIGURE 2.

The lower ends of the strut 32 extend between the innermost pair of webs38a and 38b, on the one hand, and the intermediate webs 40a and 40/5, onthe other hand, and the pivots 42a and 42b extend through aligned boresat the free ends of the strut 32, so that in this way the strut 32 isalso supported for rotary movement about the same axis as the A-frame 28and the tubular part 18. At its outer end which is distant from thebrackets 24a and 24b, the strut 32 carries a pivot on which the pulley34 is supported for free rotary movement in the manner shown mostclearly in FIGURE 2. The cable 30 is fixed at one end to the crossbar 46and extends from the latter over the pulley 34 and to the unillustratedwinch.

The support means formed by the brackets 24a and 24b is provided withstops which include frame stops to be engaged by the A-frame and strutstops to be engaged by the strut, so as to fix the lowermost operativepositions of the frame 28 and the strut 32. For this purpose the bracket24a fixedly carries between the outermost web 38a and the intermediateweb 40a a stop 5211 having a downwardly and rearwardly inclined stopsurface to be engaged by the end 44a of the frame 28. The bracket 24])has an identical stop 52b shown also in FIGURES 3, 4, and 7. This stopis fixed by any suitable web to the wall 36b.

Between the innermost webs 38a and 3812, on the one hand, and theintermediate webs 40a and 40b, on the other hand, the brackets 24a and24b respectively carry a pair of strut stops 54a and 54b which haveupwardly directed substantially horizontal stop surfaces. Actually, asis apparent from FIGURES 3, 4, and 7, the stop surfaces of the strutstops are inclined slightly downwardly toward the stern of the ship.These strut stops are also fixed by suitable webs to the walls 36a and36b of the brackets, respectively.

The above-described jettison system operates as follows:

In the stowed position the frame means 26 has the inclination indicatedin solid lines in FIGURE 1. Therefore, its center of gravity is situatedsomewhat to the left of its turning axis, as viewed in FIGURE 1. Theframe means 26 is maintained in this stowed position by the tension ofthe cable 30 when it is fully wound onto the winch. Therefore, when itbecomes necessary to discharge fluid, the winch is operated to pay outthe cable 30, and the frame means 26 will simply move downwardly aboutthe pivot axis defined by the pivots 42a and 42b due to the weight ofthe frame means 26. The tubular part 18 of the conduit means 14 will ofcourse turn about the same axis together with the A-frame 28. The cable30 is paid out until the A-frame engages the stops 52a and 52b whichsituate the A-frame in the dot-dash line position indicated in FIGURE 1.

During the initial part of the downward turning of the frame means 26,the fingers 48 at the extremities of the free ends 44a and 44b approachthe lifting strut 32, and then they engage the latter so that after theA-frame has started to turn toward its lower operative position thelifting strut 32 is constrained to turn therewith, and in this way thelifting strut 32 reaches the dot-dash line position shown in FIGURE 1.In this latter operative position of the lifting strut it engages andpresses against the stops 54a and 54b. In its operative position thelifting strut 32 extends outwardly away from the stern 10 in asubstantially horizontal direction so that the cable 30 will extend inthe direction shown in dot-dash lines in FIG- URE 1. In this way whenthe frame means 26 is returned to its stowed position the pull on thecable will extend substantially perpendicularly to the plane in whichthe frame means 26 is located, so that an eificient pulling force isprovided in this way and toggling is prevented.

When the parts have reached their operative position the fluid is pumpedout through the conduit means 14. It will be noted that as the fluiddischarges from the discharge nozzle 24 a thrust may occur urging theframe means 26 against the stops 52a and 52b, and this force istransmitted through the fingers of the A-frame to the lifting strut 32which is thus also pressed against the strut stops 54a and'54b.

I11 order to assure that the fluid is discharged from the nozzle 24 in asubmerged condition, the A-frame 28 fixedly carries at its outer tip ahorizontally extending foil 6t? which becomes situated beneath thewaterline, as indicated in FIGURE 1. The surface angle of the foil 60 issuch that due to the movement of the ship 12 the sea water flowing overthe foil will also urge the frame means 26 downwardly against the stops52a and 52b. Through these expedients, namely the flow of Water over theupper foil surface and the thrust created by the discharging fluid, theframe 28 is held down hard against its stops and is kept fromoscillating. At the same time this force is transmitted through thefingers of the A-frame to the lifting strut to maintain the latterwithout oscillation in its extended position pressing against the stops54a and 54b.

The lifting strut is desirable in those instances where the anglebetween the stowed and operating positions of the A-frame approximates180. In other cases where the angle through which the A-frame moves issubstantially less than 180 a lifting strut may not be required. Thelifting strut will provide reasonable lifting forces by way of the cable30 and will eliminate any tendency to toggle or bind.

It is to be noted that the elevation of the turning axis of the A-frameis well above the waterline so that when the frame is in its stowedposition it will be at an elevation substantially higher than thewaterline. On the other hand, in the operative position of the parts thenozzle 24 is situated preferably somewhat beneath the waterline so as todischarge the fluid directly into the sea water. If desired, the tubularpar-t 18 can be extended so that the nozzle 24 is situated out beyondthe tip of the A-frame.

When discharge of the fluid has been completed the cable 30 is rewoundonto the winch and the parts will then return to the stowed positionshown in solid lines in FIGURE 1.

The parts can be designed to discharge the fluid at the waterline, butit is preferred to provide for the discharge nozzle, in its operatingposition, an elevation no higher than the waterline and preferably anelevation somewhat below the waterline.

The jettison system described above is suitable for installation on anytype of ship stern. It does, however, adapt itself more readily to atransom type stern so that protuberances beyond the hull of the ship areminimized, thereby affording a greater measure of protection for thedevice. It is furthermore feasible to provide transom type ships with arecess for situating the jettison system of the invention within acavity built into the transom. For the sake of appearance, a cover platecan be provided and fitted on the A-frame 28.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

1. For use with a ship carrying a fluid which may have to be dischargedat sea, a jettison system comprising a pair of exterior brackets adaptedto be fixed to the ship at the exterior thereof, a pair of pivotscarried by said brackets and having a common substantially horizontalaxis, an A-frame having a pair of free ends turn- 6 ably mounted on saidpivots, so that said A-frame is swingable about said pivots from anupper stowed position where said A-frame extends upwardly from said axisto a lower operative position where said A-frame extends at least up tothe waterline, said brackets respectively carrying frame stops engagedby said A-f-rame when the latter is in said lower operative positionthereof to determine the lower position of said A-frame, a cableconnected to said A-frame for turning the latter between said positionsthereof, discharge conduit means communicating with the fluid and havingan exterior portion carried by said A-frame for movement therewith andterminating in a discharge nozzle which is situated at an elevation nohigher than the waterline when said A-frame is in said lower operativeposition thereof and foil means secured to said A-frame arranged to besituated beneath the waterline when said A-frame is in said operativeposition thereof and deriving from the movement of the ship a forceacting on said A-frame to urge the latter against said frame stops.

2. A system as recited in claim 1 and wherein said discharge conduitmeans further includes a stationary tubular part carried by the ship atits exterior, and a swivel joint fluid-tightly interconnecting saidstationary tubular part and said exterior portion, said swivel jointhaving an axis coinciding with the turning axis of said A-frame means.

3. A system as recited in claim 1 and wherein a lifting strut carries apulley which guides said cable, said lifting strut having a pair of freeends also piv-otally carried by said pivots so as to be turnable aboutthe same axis as said A-frame, and said lifting strut beingsubstantially coextensive with said A-frame, said brackets respectivelycarrying strut stops which engage said strut to limit the latter tomovement from a stowed position to an operative position where saidstrut is situated at an elevation higher than said A-frame when thelatter is in said lower operative position thereof, with said strutextending outwardly away from the ship to provide for the cable adirection which will produce eflicient movement of the A-frame, saidA-frame having fingers which respectively engage said strut duringlowering of said A-frame to said operative position thereof for turningsaid strut to said operating position thereof in response to lowering ofsaid A- frame.

4. A system as recited in claim 3 and wherein said brackets and all ofthe structure carried thereby are situated at the stern of the ship.

References Cited UNITED STATES PATENTS 2,798,364 7/ 1957 Morrison 1l4742,914,080 11/1959 Silveston 141-388 3,040,469 6/1962 Richards 114-4853,047,016 7/ 1962 Andresen 137615 FOREIGN PATENTS 278,601 10/1927 GreatBritain.

MILTON BUCHLER, Primary Examiner. ANDREW H. FARRELL, Examiner.

1. FOR USE WITH A SHIP CARRYING A FLUID WHICH MAY HAVE TO BE DISCHARGEDAT SEA, A JETTISON SYSTEM COMPRISING A PAIR OF EXTERIOR BRACKETS ADAPTEDTO BE FIXED TO THE SHIP AT THE EXTERIOR THEREOF, A PAIR OF PIVOTSCARRIED BY SAID BRACKETS AND HAVING A COMMON SUBSTANTIALLY HORIZONTALAXIS, AN A-FRAME HAVING A PAIR OF FREE ENDS TURNABLY MOUNTED ON SAIDPIVOTS, SO THAT SAID A-FRAME IS SWINGABLE ABOUT SAID PIVOTS FROM ANUPPER STOWED POSITION WHERE SAID A-FRAME EXTENDS UPWARDLY FROM SAID AXISTO A LOWER OPERATIVE POSITION WHERE SAID A-FRAME EXTENDS AT LEAST UP TOTHE WATERLINE, SAID BRACKETS RESPECTIVELY CARRYING FRAME STOPS ENGAGEDBY SAID A-FRAME WHEN THE LATTER IS IN SAID LOWER OPERATIVE POSITIONTHEREOF TO DETERMINE THE LOWER POSITION OF SAID A-FRAME, A CABLECONNECTED TO SAID A-FRAME FOR TURNING THE LATTER BETWEEN SAID POSITIONSTHEREOF, DISCHARGE CONDUIT MEANS COMMUNICATING WITH THE FLUID AND HAVINGAN EXTERIOR PORTION CARRIED BY SAID A-FRAME FOR MOVEMENT THEREWITH ANDTERMINATING IN A DISCHARGE NOZZLE WHICH IS SITUATED AT AN ELEVATION NOHIGHER THAN THE WATERLINE WHEN SAID A-FRAME